Method and apparatus for treating exhaust gas from vehicles

Abstract

A method and apparatus for treating exhaust gas produced from the combustion of fuels is disclosed. Pollutants such as unburnt hydrocarbons, carbon monoxides, oxides of nitrogen and oxides of sulfur are oxidized by ozone in an ozone contractor, and then resolved by water vapor in a muffler, so that they can be reduced.

What is claimed is:  
     
       1. A method for treating exhaust gas produced from the combustion of fuels, comprising: 
       introducing ozone into the exhaust gas in an ozone contactor which is located downstream of a catalytic converter;  
       passing the exhaust gas through a muffler having an inlet and an outlet;  
       introducing water vapor into the exhaust gas prior to the outlet of the muffler; and  
       passing the exhaust gas through at least a portion of a muffler, thereby reducing at least one pollutant, selected from a group consisting of unburnt hydrocarbons, carbon monoxide and oxides of nitrogen, from a first concentration to a second lower concentration.  
     
     
       2. The method of claim  1 , further comprising the step of: 
       producing ozone in the amount of 3 grams per hour at a fixed frequency of 600 Hz in a corona discharge type ozone generator.  
     
     
       3. The method of claim  2 , wherein the ozone is generated from air which passes through an air filter. 
     
     
       4. The method of claim  1 , further comprising the step of: 
       producing water vapor with a water evaporator which has the ratio of condensate water:water vapor=4:1.  
     
     
       5. An apparatus for treating exhaust gases produced from the combustion of fuels, comprising: 
       an ozone contactor located downstream from a catalytic converter, for mixing the exhaust gas with ozone;  
       a muffler having an inlet and an outlet;  
       a water evaporator for adding water vapor to the exhaust gas; and  
       a passageway for conducting water vapor into the muffler such that the exhaust gas stream passes through water vapor prior to exhausting from the outlet of the muffler.  
     
     
       6. The apparatus of claim  5 , further comprising 
       an ozone generator for producing ozone from air which passes through an air filter.  
     
     
       7. The apparatus of claim  5 , wherein the ozone generator is a corona discharge type. 
     
     
       8. The apparatus of claim  7 , wherein the ozone is produced in an amount of 3 grams per hour at a fixed frequency of 600 Hz. 
     
     
       9. The apparatus of claim  5 , wherein the water evaporator produces water vapor which has a ratio of condensate water:water vapor=4:1.